Quartz crucible preparation method and quartz crucible
By adding aluminum hydroxide and high-temperature pretreatment during the preparation of quartz crucibles, the content of alkaline impurities is reduced, the deformation resistance of quartz crucibles is enhanced, the problem of easy deformation of traditional quartz crucibles at high temperatures is solved, and the production efficiency and crystal quality of silicon single crystals are improved.
Patent Information
- Application Number
- CN202411029835.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-29
- Publication Date
- 2026-02-06
AI Technical Summary
Traditional quartz crucibles are prone to deformation at high temperatures, which leads to low efficiency in the silicon single crystal pulling process and affects crystal quality.
By mixing aluminum hydroxide and finished quartz sand into a mixed sand, and then subjecting it to high-temperature pretreatment and cleaning, the aluminum content is increased, the alkaline impurity content is reduced, the aluminum-alkali ratio is improved, and the deformation resistance is enhanced.
It effectively removes alkaline impurities from quartz crucibles, increases the softening point, enhances resistance to deformation, ensures normal crystal pulling, and improves production efficiency.
Smart Images
Figure CN121470779A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of quartz crucible production, and particularly relates to a quartz crucible preparation method and a quartz crucible. BACKGROUND
[0002] In a direct pulling method, an important method for producing monocrystalline silicon, a quartz crucible, as an important auxiliary part, mainly serves to bear a high-temperature silicon melt, and the quality of the quartz crucible affects not only the yield of crystal growth but also the quality of the crystal. The quartz crucible is made of high-purity quartz sand, and the purity of the quartz sand plays a decisive role in the quality of the quartz crucible. Different quartz sands have different contents of elements such as Na, K and Li, which causes different softening points and deformation resistances of the quartz crucible.
[0003] The traditional quartz crucible cannot maintain its inherent shape due to the reduction of viscosity at a working temperature of about 1600 DEG C, and various deformation problems such as local bulging and bending occur, which greatly affects the pulling process of the silicon single crystal and greatly reduces the production efficiency of the silicon single crystal. SUMMARY
[0004] To solve the above technical problems, the application provides a quartz crucible preparation method and a quartz crucible, which effectively solve the problem of high-temperature deformation of the quartz crucible in the direct pulling monocrystal process and overcome the shortcomings of the prior art.
[0005] The technical scheme adopted by the application is as follows: a quartz crucible preparation method, comprising the following steps:
[0006] Aluminum hydroxide and finished quartz sand are made into mixed sand;
[0007] The mixed sand is subjected to first heating pretreatment, so that the finished quartz sand is subjected to first crystal phase transformation;
[0008] The mixed sand is subjected to second heating pretreatment, so that the finished quartz sand is subjected to second crystal phase transformation;
[0009] The mixed sand is washed;
[0010] The mixed sand is made into a quartz crucible.
[0011] Optionally, the first heating pretreatment comprises heating to a first heating temperature and cooling to a first cooling temperature.
[0012] Optionally, the first heating temperature is 800-900 DEG C, the first heating temperature is maintained for 1-3 h, and the first cooling temperature is 100-130 DEG C.
[0013] Optionally, the second heating pretreatment comprises heating to a second heating temperature and cooling to a second cooling temperature.
[0014] Optionally, the second heating temperature is 1300-1500℃, and the second heating temperature is maintained for 3-6 hours, while the second cooling temperature is 200-300℃.
[0015] Optionally, the step involves cleaning the mixed sand, including acid washing, flotation, and water washing.
[0016] Optionally, after washing the mixed sand, the process may further include drying the mixed sand.
[0017] Optionally, after drying the mixed sand, the mixture may also be subjected to magnetic separation.
[0018] Optionally, in the mixed sand, the mass ratio of aluminum hydroxide to finished quartz sand is 0.05:1000 to 0.1:1000.
[0019] The present invention also provides a quartz crucible, which is prepared by a quartz crucible preparation method as described above.
[0020] The advantages and positive effects of this invention are as follows: By adopting the above technical solution, the crystal phase of quartz sand undergoes a transformation through high-temperature pretreatment, causing alkaline impurities in the cracks of quartz sand to accumulate on the surface of the quartz sand. At the same time, gas-liquid inclusions in the crystal lattice are effectively removed by high-temperature heating. Alkaline impurities on the surface of the quartz sand are removed by washing. By increasing the aluminum element, the aluminum-alkali ratio in the mixed sand is further increased, which improves the softening point of the quartz crucible, enhances the deformation resistance of the quartz crucible, ensures the normal crystal pulling process, and improves production efficiency. Attached Figure Description
[0021] Figure 1 This is a flowchart of a quartz crucible preparation method according to an embodiment of the present invention.
[0022] Figure 2 This is a schematic diagram of the phase transformation of quartz sand in a method for preparing a quartz crucible according to an embodiment of the present invention. Detailed Implementation
[0023] This invention provides a method for preparing a quartz crucible and a quartz crucible. The embodiments of this invention will be described below with reference to the accompanying drawings.
[0024] In the description of the embodiments of this invention, it should be understood that the terms "top," "bottom," etc., indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, it should be noted that unless otherwise explicitly specified and limited, the terms "set" and "connected" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention through specific circumstances.
[0025] like Figure 1 As shown in the figure, an embodiment of the present invention provides a method for preparing a quartz crucible, comprising the following steps: preparing a mixed sand from aluminum hydroxide and finished quartz sand; subjecting the mixed sand to a first heating pretreatment to induce a first crystal phase transformation in the finished quartz sand; subjecting the mixed sand to a second heating pretreatment to induce a second crystal phase transformation in the finished quartz sand; washing the mixed sand; and preparing the mixed sand into a quartz crucible. By adding aluminum hydroxide powder, the aluminum content is increased. Through the two pretreatment processes of high-temperature heating and washing, the impurity content of alkaline elements such as Na, K, and Li is reduced. Increasing the aluminum content while reducing the content of alkaline elements increases the aluminum-alkali ratio, i.e., the ratio of aluminum content to alkaline element content, which is beneficial to improving the softening point of the quartz crucible and enhancing its resistance to deformation.
[0026] The following is a detailed explanation of each step.
[0027] S1. Prepare mixed sand by mixing aluminum hydroxide and finished quartz sand;
[0028] It is worth noting that the finished quartz sand is high-purity quartz sand that has undergone a series of pretreatments. The production process of finished quartz sand includes ore sorting, crushing, washing, and magnetic separation. Crushing includes primary crushing, secondary crushing, and refining. Washing includes acid washing, flotation, water washing, and drying. The production process of finished quartz sand is existing technology and will not be described in detail here.
[0029] Adding aluminum hydroxide powder to finished quartz sand increases the aluminum content, which in turn improves the resistance to deformation. The aluminum hydroxide powder and finished quartz sand are then thoroughly ground and mixed to form a mixed sand. The mass ratio of aluminum hydroxide to finished quartz sand in the mixed sand is 0.05:1000 to 0.1:1000.
[0030] S2. The mixed sand undergoes a first heating pretreatment to allow the finished quartz sand to undergo its first phase transformation.
[0031] The uniformly mixed sand is placed into a crucible melting furnace for the first heating pretreatment. Electricity is applied to the electrodes inside the furnace, causing the furnace temperature to rise. Figure 2 As shown, when the temperature reaches 500–600℃, the finished quartz sand transforms from the initial β-quartz to α-quartz. When the temperature reaches the first heating temperature of 800–900℃, it is maintained at the first heating temperature and heated continuously for 1–3 hours, causing α-quartz to transform into α-phosphorus quartz. The electrodes in the melting furnace are then de-energized, and the finished quartz sand cools naturally. When the temperature drops to 150–200℃, α-phosphorus quartz transforms into β-phosphorus quartz. When the temperature drops to the first cooling temperature of 100–130℃, β-phosphorus quartz transforms into γ-phosphorus quartz.
[0032] S3. The mixed sand undergoes a second heating pretreatment to allow the finished quartz sand to undergo a second phase transformation.
[0033] When electricity is applied to the electrodes inside the melting furnace, the temperature inside the furnace rises. For example... Figure 2 As shown, when the temperature rises to 150–200℃, γ-phosphorus quartz transforms into β-phosphorus quartz. When the temperature rises to 800–900℃, β-phosphorus quartz transforms into α-phosphorus quartz. Heating to a second heating temperature of 1300–1500℃ and maintaining this temperature for 3–6 hours allows α-phosphorus quartz to transform into α-cristobalite. The electrodes in the melting furnace are then disconnected, and the finished quartz sand is allowed to cool naturally. When the temperature drops to a second cooling temperature of 200–300℃, α-cristobalite transforms into β-cristobalite.
[0034] Through the first and second heating pretreatments, the crystal phase of the finished quartz sand undergoes a transformation. As the lattice volume increases or decreases, alkaline impurities in the cracks of the finished quartz sand are enriched on the surface of the quartz sand. At the same time, the gas-liquid inclusions in the lattice, mainly hydroxyl impurities, are effectively removed by high-temperature heating.
[0035] S4. Wash the mixed sand;
[0036] It includes three processes: acid washing, flotation, and water washing. The alkaline impurities on the surface of the quartz sand are removed through washing.
[0037] After the high-temperature pretreated mixed sand is cooled to room temperature, it is soaked in a mixed acid at 15-30°C for 20-70 hours, rinsed with water, then soaked in a sodium carbonate aqueous solution with a mass concentration of 3-6% for 2-3 hours, filtered, and rinsed with water.
[0038] The acid-washed mixed sand is fed into a flotation machine and submerged in pure water at 40℃-60℃. Flotation reagents are then added for flotation. The flotation reagents consist of a mixture of ammonia, oleic acid, palmitic acid, kerosene, ammonium fluoride, and isooctanol. After flotation, the flotation liquor is filtered out and rinsed with pure water at 50℃-60℃ until the flotation liquor is completely removed.
[0039] The mixed sand after flotation was washed with deionized water.
[0040] The cleaned mixed sand is placed in a sand drying machine and dried at 780℃-810℃.
[0041] The dried mixed sand is placed in a magnetic separator for magnetic separation.
[0042] S5. Prepare a quartz crucible from the mixed sand.
[0043] The pretreated mixed sand is placed into a crucible mold and formed into a crucible shape under the action of centrifugal force. The electrodes of the crucible mold are energized to form a high-temperature electric arc, which slowly melts the mixed quartz sand and forms the crucible base. After the crucible base is melted and formed, it is naturally cooled to room temperature, demolded, sandblasted, and ground to obtain a quartz crucible.
[0044] A quartz crucible is obtained using the quartz crucible preparation method described above.
[0045] Comparative Example: A method for preparing a quartz crucible involves directly placing finished quartz sand into a crucible mold, which then forms a crucible shape under centrifugal force. Electricity is applied to the electrodes of the crucible mold to create a high-temperature electric arc, slowly melting the mixed quartz sand and forming the crucible substrate. After the crucible substrate has melted and solidified, it is naturally cooled to room temperature, demolded, sandblasted, and ground to obtain the quartz crucible.
[0046] Example 1: A method for preparing a quartz crucible, comprising the following steps:
[0047] S1: Aluminum hydroxide and finished quartz sand are mixed to form a sand mixture;
[0048] Aluminum hydroxide powder and finished quartz sand are thoroughly ground and mixed evenly to form mixed sand. The mass ratio of aluminum hydroxide to finished quartz sand in the mixed sand is 0.05:1000.
[0049] S2. The mixed sand undergoes a first heating pretreatment to allow the finished quartz sand to undergo its first phase transformation.
[0050] The first heating pretreatment includes heating to a first heating temperature and cooling to a first cooling temperature. The first heating temperature is 800°C, the heating is maintained at the first heating temperature for 1 hour, and the first cooling temperature is 100°C.
[0051] S3. The mixed sand undergoes a second heating pretreatment to allow the finished quartz sand to undergo a second phase transformation.
[0052] The second heating pretreatment includes heating to a second heating temperature and cooling to a second cooling temperature. The second heating temperature is 1300℃, and the second heating temperature is maintained for 3 hours. The second cooling temperature is 200℃.
[0053] S4. Wash the mixed sand;
[0054] After the high-temperature pretreated mixed sand was cooled to room temperature, it was soaked in a mixed acid at 15°C for 20 hours and then rinsed with water. After that, it was soaked in a 3% sodium carbonate aqueous solution for 2 hours, filtered, and then rinsed with water.
[0055] The acid-washed mixed sand is fed into a flotation machine and submerged in 40°C pure water. Flotation reagents are then added for flotation. The flotation reagents consist of a mixture of ammonia, oleic acid, palmitic acid, kerosene, ammonium fluoride, and isooctanol. After flotation, the flotation liquor is filtered out and rinsed with 50°C pure water until the flotation liquor is completely removed.
[0056] The mixed sand after flotation was washed with deionized water.
[0057] The cleaned mixed sand is placed in a sand drying machine and dried at 780℃.
[0058] The dried mixed sand is placed in a magnetic separator for magnetic separation.
[0059] S5. Prepare a quartz crucible from the mixed sand.
[0060] The pretreated mixed sand is placed into a crucible mold and formed into a crucible shape under the action of centrifugal force. The electrodes of the crucible mold are energized to form a high-temperature electric arc, which slowly melts the mixed quartz sand and forms the crucible base. After the crucible base is melted and formed, it is naturally cooled to room temperature, demolded, sandblasted, and ground to obtain a quartz crucible.
[0061] Example 2: A method for preparing a quartz crucible, comprising the following steps:
[0062] S1: Aluminum hydroxide and finished quartz sand are mixed to form a sand mixture;
[0063] Aluminum hydroxide powder and finished quartz sand are thoroughly ground and mixed evenly to form mixed sand. The mass ratio of aluminum hydroxide to finished quartz sand in the mixed sand is 0.08:1000.
[0064] S2. The mixed sand undergoes a first heating pretreatment to allow the finished quartz sand to undergo its first phase transformation.
[0065] The first heating pretreatment includes heating to a first heating temperature and cooling to a first cooling temperature. The first heating temperature is 870°C, the heating time is 2 hours, and the first cooling temperature is 117°C.
[0066] S3. The mixed sand undergoes a second heating pretreatment to allow the finished quartz sand to undergo a second phase transformation.
[0067] The second heating pretreatment includes heating to a second heating temperature and cooling to a second cooling temperature. The second heating temperature is 1470℃, the heating time is 5 hours, and the second cooling temperature is 268℃.
[0068] S4. Wash the mixed sand;
[0069] After the high-temperature pretreated mixed sand was cooled to room temperature, it was soaked in a mixed acid at 120°C for 50 hours and then rinsed with water. After that, it was soaked in a 5% sodium carbonate aqueous solution for 2.5 hours, filtered, and rinsed with water.
[0070] The acid-washed mixed sand is fed into a flotation machine and submerged in 50°C pure water. Flotation reagents are then added for flotation. The flotation reagents consist of a mixture of ammonia, oleic acid, palmitic acid, kerosene, ammonium fluoride, and isooctanol. After flotation, the flotation liquor is filtered out and rinsed with 55°C pure water until the flotation liquor is completely removed.
[0071] The mixed sand after flotation was washed with deionized water.
[0072] The cleaned mixed sand is placed in a sand drying machine and dried at 790℃.
[0073] The dried mixed sand is placed in a magnetic separator for magnetic separation.
[0074] S5. Prepare a quartz crucible from the mixed sand.
[0075] The pretreated mixed sand is placed into a crucible mold and formed into a crucible shape under the action of centrifugal force. The electrodes of the crucible mold are energized to form a high-temperature electric arc, which slowly melts the mixed quartz sand and forms the crucible base. After the crucible base is melted and formed, it is naturally cooled to room temperature, demolded, sandblasted, and ground to obtain a quartz crucible.
[0076] Example 3: A method for preparing a quartz crucible, comprising the following steps:
[0077] S1: Aluminum hydroxide and finished quartz sand are mixed to form a sand mixture;
[0078] Aluminum hydroxide powder and finished quartz sand are thoroughly ground and mixed evenly to form mixed sand. The mass ratio of aluminum hydroxide to finished quartz sand in the mixed sand is 0.1:1000.
[0079] S2. The mixed sand undergoes a first heating pretreatment to allow the finished quartz sand to undergo its first phase transformation.
[0080] The first heating pretreatment includes heating to a first heating temperature and cooling to a first cooling temperature. The first heating temperature is 900°C, the heating time is 3 hours, and the first cooling temperature is 130°C.
[0081] S3. The mixed sand undergoes a second heating pretreatment to allow the finished quartz sand to undergo a second phase transformation.
[0082] The second heating pretreatment includes heating to a second heating temperature and cooling to a second cooling temperature. The second heating temperature is 1500℃, the heating time is 6 hours, and the second cooling temperature is 300℃.
[0083] S4. Wash the mixed sand;
[0084] After the high-temperature pretreated mixed sand was cooled to room temperature, it was soaked in a mixed acid at 30°C for 70 hours and then rinsed with water. After that, it was soaked in a 6% sodium carbonate aqueous solution for 3 hours, filtered, and then rinsed with water.
[0085] The acid-washed mixed sand is fed into a flotation machine and submerged in 60°C pure water. Flotation reagents are then added for flotation. The flotation reagents consist of a mixture of ammonia, oleic acid, palmitic acid, kerosene, ammonium fluoride, and isooctanol. After flotation, the flotation liquor is filtered out and rinsed with 60°C pure water until the flotation liquor is completely removed.
[0086] The mixed sand after flotation was washed with deionized water.
[0087] The cleaned mixed sand is placed in a sand drying machine and dried at 810℃.
[0088] The dried mixed sand is placed in a magnetic separator for magnetic separation.
[0089] S5. Prepare a quartz crucible from the mixed sand.
[0090] The pretreated mixed sand is placed into a crucible mold and formed into a crucible shape under the action of centrifugal force. The electrodes of the crucible mold are energized to form a high-temperature electric arc, which slowly melts the mixed quartz sand and forms the crucible base. After the crucible base is melted and formed, it is naturally cooled to room temperature, demolded, sandblasted, and ground to obtain a quartz crucible.
[0091] Quartz crucibles were prepared using the methods described in the comparative examples, Example 1, Example 2, and Example 3. 110mm × 50mm sample blocks were longitudinally cut from the straight walls of each of the four crucibles. The samples were placed horizontally on a heat-resistant support with a span of 150mm and then placed in a single-crystal furnace for constant temperature firing at 1400±10℃. After natural cooling to room temperature in the single-crystal furnace, the samples were removed, and the change in arch height ΔH was measured. The high-temperature deformation rate T was calculated using the following formula:
[0092] T = △H / 110 × 100%
[0093] T—High-temperature deformation rate;
[0094] △H—Change in the arch height of the specimen, mm
[0095] The results are shown in the table below:
[0096] Type Comparative Example Example One Example Two Example Three Strain (%) 0.45 0.29 0.18 0.27
[0097] As shown in the table above, the deformation rate of the quartz crucible prepared using this technical solution is significantly reduced, and its deformation resistance is effectively improved.
[0098] The advantages and positive effects of this invention are as follows:
[0099] 1. Through high-temperature pretreatment, the crystal phase of quartz sand is transformed, causing alkaline impurities in the crack gaps of quartz sand to accumulate on the surface of quartz sand. At the same time, gas-liquid inclusions in the crystal lattice are effectively removed by high-temperature heating.
[0100] 2. The alkaline impurities in the quartz sand are removed by washing;
[0101] 3. By increasing the aluminum content, the aluminum-alkali ratio in the mixed sand was further increased, which improved the softening point of the quartz crucible, enhanced its resistance to deformation, ensured the normal crystal pulling process, and improved production efficiency.
[0102] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.
Claims
1. A method for preparing a quartz crucible, characterized in that, Includes the following steps: Aluminum hydroxide and finished quartz sand are mixed to form a sand mixture; The mixed sand is subjected to a first heating pretreatment to cause the finished quartz sand to undergo a first crystal phase transformation; The mixed sand is subjected to a second heating pretreatment to cause the finished quartz sand to undergo a second crystal phase transformation; The mixed sand is then washed; The mixed sand is made into a quartz crucible.
2. The method for preparing a quartz crucible according to claim 1, characterized in that: The first heating pretreatment includes heating to a first heating temperature and cooling to a first cooling temperature.
3. The method for preparing a quartz crucible according to claim 2, characterized in that: The first heating temperature is 800-900℃, and the heating is maintained at the first heating temperature for 1-3 hours. The first cooling temperature is 100-130℃.
4. The method for preparing a quartz crucible according to claim 3, characterized in that: The second heating pretreatment includes heating to a second heating temperature and cooling to a second cooling temperature.
5. The method for preparing a quartz crucible according to claim 4, characterized in that: The second heating temperature is 1300-1500℃, and the heating is maintained at the second heating temperature for 3-6 hours. The second cooling temperature is 200-300℃.
6. A method for preparing a quartz crucible according to any one of claims 1-5, characterized in that: The step involves cleaning the mixed sand, including acid washing, flotation, and water washing.
7. The method for preparing a quartz crucible according to claim 6, characterized in that: After washing the mixed sand, the process also includes drying the mixed sand.
8. The method for preparing a quartz crucible according to claim 7, characterized in that: After drying the mixed sand, the process also includes magnetic separation of the mixed sand.
9. A method for preparing a quartz crucible according to any one of claims 1-5 and 7-8, characterized in that: The mass ratio of aluminum hydroxide to finished quartz sand in the mixed sand is 0.05:1000 to 0.1:1000.
10. A quartz crucible, characterized in that: The quartz crucible is prepared using a quartz crucible preparation method as described in any one of claims 1-9.